uniform vec3 iResolution;
uniform float iTime;
uniform vec2 iMouse;

mat2 m(float a){float c=cos(a), s=sin(a);return mat2(c,-s,s,c);}
float map(vec3 p){
  p.xz*= m(iTime*0.4);p.xy*= m(iTime*0.3);
  vec3 q = p*2.+iTime;
  return length(p+vec3(sin(iTime*0.7)))*log(length(p)+1.) + sin(q.x+sin(q.z+sin(q.y)))*0.5 - 1.;
}

void main() {
  vec2 p = gl_FragCoord.xy/iResolution.y - vec2(.9,.5);
  vec3 cl = vec3(0.);
  float d = 2.5;
  for(int i=0; i<=5; i++) {
    vec3 p = vec3(0,0,5.) + normalize(vec3(p, -1.))*d;
    float rz = map(p);
    float f =  clamp((rz - map(p+.1))*0.5, -.1, 1. );
    vec3 l = vec3(0.1,0.3,.4) + vec3(5., 2.5, 3.)*f;
    cl = cl*l + smoothstep(2.5, .0, rz)*.7*l;
    d += min(rz, 1.);
  }
  gl_FragColor = vec4(cl, 1.);
}